Synthesis of Porous Carbon Nanosheets and Its Application in Sodium-Ion Battery
- 2015年第21卷 
本文以氯化钠为硬模板、硝酸镍为金属源、葡萄糖为碳源，在氮气气氛中于750 oC通过一步热解法合成嵌镍碳纳米片，然后经酸处理得到多孔碳纳米片. 通过扫描电镜（SEM）、透射电镜（TEM）、拉曼光谱（Raman）和比表面积测定（BET）表征多孔碳纳米片的形貌和结构. 结果显示：多孔碳纳米片孔分布均匀，孔径大小均一；经过酸处理后，碳材料的石墨化程度降低；具有较大的比表面积（约340 m2•g-1）. 电化学测试表明，电极在100 mA•g-1电流密度下，经过200周循环放电后比容量可维持在309.4 mAh•g-1，甚至在1000 mA•g-1 的大电流下其放电比容量仍然可达到173 mAh•g-1，表现出良好的循环稳定性和倍率性能，其在钠离子电池负极材料方面具有潜在的应用前景.Owning to sodium’s high abundance, relatively low cost, similar chemical properties to Li and very suitable redox potential of E0(Na+/Na) = -2.71 V versus SHE which is only 0.3 V above that of lithium, rechargeable sodium ion battery hold much promise as potential alternatives to current lithium ion batteries for energy storage applications. Carbon material is regarded as the most promising anode candidate for sodium ion battery. Particularly, carbon nanosheet with porous structure and high conductivity is expected to have improved sodium ion storage properties. In this paper, we present a two-step pyrolysis-based method for facile synthesis of porous carbon nanosheets with high capacity as anode in sodium-ion battery. In this method, sodium chloride was selected as a hard template, nickel nitrate as the metal source and glucose as the carbon source with pyrolysis temperature of 750 °C in nitrogen atmosphere. The first obtained is Ni-incorporated carbon nanosheets which were refluxed with dilute hydrochloric acid to produce uniform porous carbon nanosheets. TEM images shows that the pores in the as-prepared porous nanosheets spread evenly with narrow-distributed diameter; Raman spectra indicate that the graphitic degree of the product decreases after acid treatment; BET results demonstrate that the specific surface area can reach 340 m2•g-1; Electrochemical characterization says that the as-prepared porous nanosheets have excellent Na+ storage rate capability of 173 mAh•g-1 at 1000 mAh•g-1 and exhibit outstanding cycle stability at 100 mA•g-1 with 309.4 mAh•g-1 capacity even after 200-cycle running. The super sodium ion storage performance of the produced carbon nanosheets could be attributed to the specific structure, where the interconnected micro- and meso-pores inside minimized the diffusion lengths and the 2D carbon nanosheet structure enhanced electronic conductivity. These results show that the porous carbon nanosheet is a promising anode material for sodium ion batteries.